1. Field of the Invention
The present invention is related to a two-stage lens driving device, in particular to a lens driving device that uses an electromagnetic driving device as a power source to drive a lens holder so as to undergo switching between two positions.
2. Description of the Prior Art
Referring to FIG. 1, a general photo device 1 mainly comprises a lens set 11 and a sensitive member 12, wherein the lens set 11 provides the image of an object to the sensitive member 12. If a distance between the lens set 11 and the sensitive member 12 is fixed (fixed focus lens), the photo device 1 can only take a clear image of an object with 2-3 meters of a hyperfocal distance. In order to shoot in a little distance, a separate lens driving device (not shown) can be used to drive the lens set 11 to change the distance between the lens set 11 and the sensitive member 12 for focusing.
If the lens set 11 has a zooming function, a plurality of lenses in the lens set 11 may collocate the operation of varying the focal lengths. Meanwhile, the lens driving device in the lens set is necessary to drive the plurality of lenses.
A mechanism for zooming or varying the focal length of a prior two-stage lens is manually controlled but inconvenient. The present invention overcomes this drawback through the use of electromagnetism and reduces the volume of the lens driving device by simplifying the mechanism so as to decrease manufacturing costs and enhance the assembly process. Hence, the miniaturized lens driving device can be applied to photographing modules utilized in mobile phones, laptops, PDAs, etc.
Although U.S. Pat. Nos. 5,150,260, 6,392,827, 5,220,461, and 5,471,100 have disclosed arrangements related to the lens driving device, the present invention is unlike these prior art configurations.